The present invention relates generally to ventilation hoods and more specifically to an apparatus and system for safely and efficiently ventilating the area above a stovetop or similar cooking device using a compact low-noise device.
Cooking creates undesirable by-products, such as heat, steam, grease and odors. These cooking by-products pollute the air in a home or commercial environment if they are not safely removed. These cooking by-products are irritating, harmful and potentially hazardous. Accordingly, a multitude of ventilation systems have been developed to draw the cooking by-products away from the immediate vicinity of the cooking area and to expel this contaminated air to an external environment through an exhaust duct.
The heat generated from cooking expands the air in the cooking area and it rises, carrying with it the cooking by-products. Typical ventilation systems use a hood placed above the cooking area to capture the by-products prior to removal by a blower system. The hood is like a small room wherein too much airflow is as harmful as too little. If too much air is removed from a well insulated home, a negative pressure results rendering the ventilation system ineffective unless expensive make-up air is introduced. As a result the blower system should be sized based on the expected usage of the cooking area. For example, a barbecue grill, or wok should be measured at full value because they are most often at the high setting. Multiple burners, however, are rarely all turned to the high setting at any one time and should be discounted.
If the size of the blower system is too small, the fan will under-exhaust allowing heat and/or cooking by-products to escape from the hood into the kitchen and, perhaps, the rest of the facility. On the other hand, if the size of the blower system is too large, the fan will over-exhaust allowing too much air to be expelled while the motor is consuming energy unnecessarily. As a result, the air heated or cooled by the air conditioning system of the building is also exhausted to the outside, causing the thermostat of the air conditioner to run the air conditioning system to replace the exhausted air. This resulting inefficiency increases the owner""s utility bills and needlessly wastes energy.
Another factor limiting the airflow capacity of the blower system relates to the physical size of the hood itself. In many cases, the optimal airflow rating for a traditional blower system can only be achieved using a hood that is unacceptably large, both physically and aesthetically, to many potential users and purchasers of the hood.
Finally, blower noise is a major concern for many installations, especially in residential applications. As a result, less-than-optimal airflow capacity is often accepted to reduce the blower noise.
The present invention provides a method and apparatus for ventilating the area above a cooking area. The present invention provides a ventilation hood system for exhausting air containing cooking by-products from a cooking station to an external environment through an exhaust duct.
The ventilation hood system of the present invention is designed to minimize the size of the hood, particularly in the vertical dimension, while at the same time optimizing the airflow through the hood in order to thoroughly evacuate the cooking by-products. Prior low-profile hoods have been developed, but such hoods have exhibited insufficient airflow capability for use in many applications. The ventilation hood of the present invention accomplishes both goals in a compact, low-noise device. As such, the ventilation hood of the present invention represents a significant improvement over prior ventilation hoods.
The ventilation hood system of the present invention incorporates a hood, a blower unit and a blower control unit. The hood is of sufficient size and design to hold the cooking by-products prior to evacuation from the hood. The blower unit is disposed within the hood and capable of removing the cooking by-products from within the hood and liquefying and containing grease. The blower control unit may incorporate a speed controller having variable settings, such as a first, second and third setting.
In contrast to prior designs, the method and apparatus of the present invention draws hot air and cooking by-products in from the upper portion of the hood, where such hot air and cooking by-products naturally rise. The hot air and cooking by-products are drawn down into the center of the blower by the rotary action of a radial fan disposed in the lower portion of the blower.
In a first embodiment of the present invention, the invention is an apparatus for ventilating a hood apparatus incorporating an upper plenum frame having an inlet and having an outlet disposed in the bottom thereof acting in concert with a lower plenum having an inlet disposed in the top thereof connected to the outlet of the upper plenum frame and having an outlet. The apparatus also incorporates a squirrel cage fan disposed within the lower plenum having an inner profile and an axis, the axis disposed vertically and the inner profile of the squirrel cage fan being disposed about the inlet of the lower plenum.
In a second embodiment, the invention is an apparatus for ventilating a hood apparatus having an upper inner surface, the apparatus incorporating a substantially-rectangular upper frame mounted to the hood and disposed substantially parallel to, and a fixed distance from, the upper inner surface of the hood and having a circular outlet disposed in the bottom thereof. The apparatus also incorporates a lower plenum having a circular inlet disposed in the top thereof connected to the circular outlet of the upper plenum frame and having an outlet on the side thereof. Finally, the apparatus incorporates a squirrel cage fan disposed about a fan motor within the lower plenum, having an inner profile and an axis, the axis disposed vertically and the inner profile of the squirrel cage fan being disposed about the circular inlet of the lower plenum.